Joseph m



naar Sim JoSEPH M. WILSON,v or PHILADELPHIA, PENNSYLVANIA.

Letters PateIit'No. 12,878, dated March 21, 1871. I

IMPROVEMENT |N cLs'l-ER-BLoczicS AND PIER oR ABu'rMENT-PLATES Fon BRIDGES AND 'RooF-TnussEs.

The Schedule referred to in mese Letters Patent and making part of the same.

To all whom. it may concern Be it known that I,IJoSEPH M. WILSON, of the city and county of Philadelphia, in the State of Pennsylvania, have invented a new and useful Improvement in Bolster-Blocks andPier or Abutment-Plates for ridges, Roof-Trusses, 85e.; and I do hereby declare the following to be a full, clear, and exact description thereof, which will enable others skilled inthe art to which it appertains to make and use my invention,

reference being had to the accompanying drawing which forms a part of' this specification, and in which- Figures 1 and are side views of my invention applied to opposite butments, and

Figure 3, a transverse section of fthe same as shown in g. 2. l

' The same parts are denoted by the same letters in all the figures. 'i

. I construct theplates and bolster-blocks entirely of steelor wrought-iron. A

Io the plate D, which rests on vthe .pier or abutment, are bolted or riveted the strips E EI F F, by which not only is the .platestrengthenech but the .strips E E forni a railway for the rollers C 0,whicl1 immediately support the bolster-block. These rollers are constructed with flanges, as shown, to prevent lateral displacement.

The lower portion Blof the bolster-block I prefer to4 make of the arched or U-shape, shown inthe drawing, and to this part B I bolt or rivet the cheeks or lugs A A, through which passes the pin G that'connects the bolster-block with the post H H and chord I I, as shown. y

Whenthe invention is applied to a roof-truss the pin G is passed through the rafter and tie-beam.

The rollers O O support the bolster-block at that e'nd of the chord or tie-beam which is to be movable,

so as to permit of self-adj ustm'entunder expansion or.

contraction.

rlhe bolster-block at the opposite andked endrests A and described.

' vJ OS.' M. WILSON.

Witnesses:

S. E. POTTER, L BURTT. 

